Talking about oils (again) -MBUSA changed the policy to use synthetic after year 2000 and our 1998 ML320 run on dino oils for few years making 13,000 intervals (dictated by FSS) just fine.
Even my vehicles don't require synthetics, I do use them as the price difference is not that big in US and I appreciate additional protection.
Like last year oil pump failed on our W124 and I run the engine for few minutes with no oil pressure. I checked it out later, while replacing the head gasket and the cylinders at 292k miles are still having perfect honing marks from Stuttgart.
Also switching to synthetic the engines drop oil usage. That always coming with me fixing old orings, so not real proof, but I like the impression.
BTW my stepbro divorced Dutch wife after 20 years of marriage, so the "harder to get is appreciated longer" did not work in this case.

Dino oil with 13k intervals (if I get it right)? In miles? I believe you're using fleece filter. But really, if that is the case, dino oils must have improved very well lately. What brand with what approval number is that dino you're using? I'm asking this simply to get feedback from an actual practical experience. Sorry to impose like this.

With the semi-synthetic I'm using, oil pressure is doing very well. In worst cases with coolant temp at 100 the pressure goes down to 1.5 bar on drive. Hopefully the oil pump has ages to go.

Dino oil with 13k intervals (if I get it right)? In miles? I believe you're using fleece filter. .

That was back in 1997-2000 when dealers used dino oils on Mercedes. I believe they put paper filters at the time as well, but for warranty period I was servicing the car at dealer and opened the hood only 2 times.